Giving the Second Ingredient Its Due

Giving Tonic Its Due

The gin and tonic as imagined at La Vara, with lemon peel climbing out of the glass.

Tony Cenicola / The New York Times

By ERIC ASIMOV

May 21, 2013

The major components of a gin and tonic are right in the name of the cocktail. Though tonic is clearly secondary, it cannot be ignored or waved in the vague direction of the spirit, as some bartenders do with vermouth when making a martini. Tonic’s flavors are assertive, easily discernible and crucial to the composition. Without it, a gin and tonic is simply a bad martini.

Even so, the tonic is easily taken for granted, which is fine — as long as you don’t pay attention to the gin, either, or the lime or the ice. For just as the quality and character of gins can vary widely, so, too, can tonics. The choice of a tonic produces very different cocktails, as I found in a recent blind tasting of six tonics.

The tasting took place, appropriately, at the Gin Palace, a cocktail bar in the East Village with 64 varieties of gin. I was joined by Rosie Schaap, the drinks columnist for The New York Times Magazine and author of the memoir “Drinking With Men.” Before each of us were six gin and tonics, all mixed by Frank Cisneros, the beverage director, all made with Beefeater gin, an excellent benchmark London dry gin.

Mr. Cisneros, naturally, takes tonic seriously. As with many high-end cocktail lounges, he makes his own (three, actually) and has Bittermens Commonwealth, which is a tonic liqueur, and Q, a good commercial tonic that was the third favorite in our tasting.

What is tonic? Like its partner gin, tonic can be a blend of many different things, depending on the recipe, which is generally proprietary. But, also like gin (which, no matter what other ingredients, must begin with juniper berries), tonic must start with quinine, which is derived from the bark of the cinchona tree of South America.

Quinine was originally used for medicinal purposes. It was the first effective protection against malaria, and those tonics generally contained far more quinine than tonics do today. As a cocktail mixer, quinine is blended with carbonated water and mixed with a sweetener and other botanicals, like lemon grass, citrus zest and spices.

With tonic as the only variable, the cocktails presented six very different flavor profiles. Our favorite, for its clean, bittersweet flavor and fine effervescence, was the widely available (and much less expensive) Schweppes. Two high-end tonics, Fentimans and Q, followed closely behind.

No. 4 was Fever-Tree Naturally Light, which happened to be Rosie’s house tonic. (“It doesn’t make too many demands,” she said.) Then came Canada Dry, which seemed a bit indistinct, and, last, Fever-Tree Premium, which differs from the Naturally Light by using cane sugar instead of pure fructose. We found it far too sweet.

Aside from the proprietary additions, generally identified in the ingredients as “natural flavor,” a major difference among the tonics was the choice of sweeteners. Schweppes and Canada Dry were cagey, listing “high fructose corn syrup and/or sugar.” Even though Schweppes topped our selection, Mr. Cisneros said that he, personally, would not use a mixer with high-fructose corn syrup in his bar.

“We want a level of craftsmanship and purity and farm-to-table mentality that communicates what we’re trying to do with cocktails,” he said. “High-fructose corn syrup is an extra level of processing.”

Mr. Cisneros uses none of the tonics we tried, instead making his own using cinchona bark, lemon grass, lime and grapefruit zest and allspice berries, which he boils into a syrup. To make a gin and tonic, he mixes it with gin and tops it with soda.

The three tonics he makes vary depending on the proportion of botanicals he uses or omits. He then selects a particular tonic depending on which spirit it is meant to accompany.

I tasted one he made with eucalyptus and mint, and another with pepper. Both, and the base tonic he makes, are light in texture, a touch more bitter than commercial tonics and slightly less sweet.

“Tonic is just as important as the gin,” he said, “but it’s a pain in the butt to make.”

★★★ 1/2 SCHWEPPES TONIC WATER, 1-LITER BOTTLE $1.89

Clean, bittersweet and refreshing, with a fine but insistent carbonation and clear quinine and citrus flavor.

★★★ FENTIMANS TONIC WATER, FOUR 9.3-OUNCE BOTTLES $7.99

Complex, clean, fruity with fine effervescence and just a touch of sweetness.